The present invention relates to a process for extracting metals from a copper-sulfidic and/or copper/iron-sulfidic ore or ore concentrate.
By far the biggest part of the world""s copper production (about 90%) is extracted from copper sulfide minerals. Among the copper sulfide minerals, there may be mentioned, above all, chalcopyrite (CuFeS2), bornite (Cu5FeS4), cubanite (CuFeS4), chalcosine (Cu2S), digenite (Cu9S5), covelline (CuS), enargite (Cu3AsS4), tennantite (Cu12As4S13) and tetrahedrite (Cu12Sb4S13).
Among the copper sulfide minerals, chalcopyrite is the most widespread mineral; therefore, it is of the greatest scientific and economic importance in the development of new extraction methods.
In addition, chalcopyrite is characterized by always containing deposited gold, platinum metals and other rare metals as well as rare earths.
The copper sulfide minerals are extracted from ores, which are usually milled and concentrated by a flotation process to yield an ore concentrate, whereby a substantial part of the silicates contained in the ground stock, in particular, is separated off.
Today, in addition to the known pyrometallurgical and hydrometallurgical processes, there are various approaches to leaching copper and other metals occurring in the copper sulfide minerals from the ores or ore concentrates using bioleaching processes. This involves the problem that only about 20% of the copper contained in chalcopyrite can be leached out using the known processes because passivation of the chalcopyrite occurs.
Although a large number of attempts to avoid the passivation of chalcopyrite have been successfully performed on a laboratory scale, no utilizable process technology for metal extraction could be derived therefrom to date.
Thus, it has been the object of the invention to provide an improved process for extracting copper and other metals from chalcopyrite.